diff options
Diffstat (limited to 'drivers/vfio/vfio_main.c')
| -rw-r--r-- | drivers/vfio/vfio_main.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 902f06e52c48..5417778f2b6b 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -935,6 +935,53 @@ static int vfio_ioctl_device_feature_migration(struct vfio_device *device, return 0; } +void vfio_combine_iova_ranges(struct rb_root_cached *root, u32 cur_nodes, + u32 req_nodes) +{ + struct interval_tree_node *prev, *curr, *comb_start, *comb_end; + unsigned long min_gap, curr_gap; + + /* Special shortcut when a single range is required */ + if (req_nodes == 1) { + unsigned long last; + + comb_start = interval_tree_iter_first(root, 0, ULONG_MAX); + curr = comb_start; + while (curr) { + last = curr->last; + prev = curr; + curr = interval_tree_iter_next(curr, 0, ULONG_MAX); + if (prev != comb_start) + interval_tree_remove(prev, root); + } + comb_start->last = last; + return; + } + + /* Combine ranges which have the smallest gap */ + while (cur_nodes > req_nodes) { + prev = NULL; + min_gap = ULONG_MAX; + curr = interval_tree_iter_first(root, 0, ULONG_MAX); + while (curr) { + if (prev) { + curr_gap = curr->start - prev->last; + if (curr_gap < min_gap) { + min_gap = curr_gap; + comb_start = prev; + comb_end = curr; + } + } + prev = curr; + curr = interval_tree_iter_next(curr, 0, ULONG_MAX); + } + comb_start->last = comb_end->last; + interval_tree_remove(comb_end, root); + cur_nodes--; + } +} +EXPORT_SYMBOL_GPL(vfio_combine_iova_ranges); + /* Ranges should fit into a single kernel page */ #define LOG_MAX_RANGES \ (PAGE_SIZE / sizeof(struct vfio_device_feature_dma_logging_range)) |